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violet_z6

Seed Sprouting and Temperatures

Violet_Z6
18 years ago

For all those germinating seeds, I thought this table might be of some use to pass along:

"How long does it take for those seeds to sprout? At 40 degrees F, carrots take 50 days to sprout. 50 DAYS! Wow that is almost 2 MONTHS, of course the soil warms gradually so they finally do sprout sooner but think of all the bad things that can happen to those seeds in that time period.

Now look at the time to sprout in the late summer when the soil temperature might be around 70 degrees. Carrots take 6 days ! What a difference - the same is true of every other type of seed.

Beets: 40 days versus 6 days.

Onions: 30 days versus 4 days.

Peas: 40 days versus 7 days.

Spinach: 25 days versus 5 days."

So 80ðF - 85ðF is optimum for the most rapid germination. Greenhouses know this which is why they often use heating pads under their seed trays to make the most efficient use of time management.

Comments (20)

  • calken
    18 years ago

    Wow! Fantastic information for a newbie like myself. Thank you.

  • ilovecheese
    18 years ago

    very helpful

  • byron
    18 years ago

    FWIW

    That chart is in Nancy Bubels "New Seed Starters Hanbook"

    Also the 100f results.

    Byron

  • naturalstuff
    18 years ago

    violet, very interesting! Thanks for that. Although I didn't think anything would germinate at 40 degrees. Learn something new everyday. How about Pumpkins? :( I don't see any pumpkins in there.

  • good_gardening1
    18 years ago

    No peanuts either....

    But I'm just being picky....

    Great chart,

    Thank You!

  • Bethany873
    18 years ago

    I would guess pumpkins and other squash to be silimar to melons

  • Violet_Z6
    Original Author
    17 years ago

    >naturalstuff
    >How about Pumpkins?

    >good_gardening1
    >No peanuts either

    I think the point is being missed here - which is the hotter the soil (around 85) the better for almost all seeds.

  • digit
    17 years ago

    Thanks Violet,

    Well, there you have it. My wife is always in a hurry to get seed planted outdoors. I tell her to take off her shoes and get a feel for what kind of environment she's offering the seeds.

    A couple things attract my interest in the chart:

    1 - Altho' a cool, bright utility room might be about the best place inside a home for growing plant starts, the cool temperature, which keeps the plants from stretching while they're not getting quite full sunshine, will interfere with the sprouting of seeds of eggplant or peppers. (We start all of our early crops on top of the refrigerator in a warm kitchen. It's above 70 degrees up there, day and night.

    2 - Many of us think of peas as the earliest vegetable to plant but you can see that spinach, lettuce, and radishes germinate more quickly at low temperatures. Salads first!

    Germination temperatures aren't the entire story for getting things off to a quick start, of course. In fact, if high temperatures continue some vegetables can get into trouble - peas, again as an example. Our first planting of peas came up fairly well but shortly after planting pea seed again, we were hit with record highs - over 90 on a couple of days! The 2nd planting of peas virtually SHOT out of the ground. Meanwhile, the 1st planting began to look rather exhausted. They are vining but the leaves were much smaller than usual. The 1st planting seems a lot happier now that the temperatures have moderated.

    They have neither thermal underwear and mukluks nor a parasol and flip flops. For many of our garden vegetables - if the temperatures would seem pleasant to us au naturel, they're happy.

    Steve

  • Violet_Z6
    Original Author
    17 years ago

    That's why I say "almost" all seeds Steve. There are always exceptions such as peas but if you look at the chart peas germinate the quickest at 86F degrees.

    Notice that another main salad ingredient lettuce germinates most quickly between 77F and 86F Degrees which soil temps are rarely at in early spring.

    This simply shows that most seeds germinate best when soil temperatures are - as you hint at - warm to the feet.

    ;)

  • paulns
    17 years ago

    Thanks Violet. I've succumbed once more to my wife's anxiety about getting seeds into the ground early, even though they seem to do nothing - or worse, rot or get eaten - whenever I do. I need to work on my soothing reassuring voice. :)

    Why the h*ll do seed packets for lettuce, spinach etc. say 'plant as soon as the ground can be worked'?

  • skagit_goat_man_
    17 years ago

    We're in the middle of moving and my books are all packed so I can't give you the reference. But the quick time to germination at 86 degrees is only part of the story. The other part is what % of the seeds germinate. There you will find that seeds at lettuce will give a higher germination % at 65 degrees than 86. Tom

  • Violet_Z6
    Original Author
    17 years ago

    There are always other variables in "the big picture".

    I suppose most gardeners aren't too worried about lettuce seeds since it doen't take that many plants to feed one human in a home garden and each packet always has hundreds - if not thousands of seeds. It's a good way for a home gardener to experiment and succession plant at the same time. Keep a journal. Sow early and see how long it takes, then sow later for more lettuce when the soil temp is higher and log days to germination.

    Most gardeners assume seeds will start once they put them in the ground and then wonder why they don't come up within three days. Nature just doesn't work that way. Anxious gardeners who've been cooped up all winter are eager to dive in and easily get frustrated when they don't get immediate results.

    It is possible to sow seeds all winter - outside - literally. Just check out the Winter Sowing Forum and FAQ.

    >Why the h*ll do seed packets for lettuce, spinach etc. say 'plant as soon as the ground can be worked'?

    We're not saying they won't germinate if the soil is colder, it will just take longer. So you can sow early and wait two weeks or sow a little later and wait a few days. But if you don't sow them at all you obviously get nothing.

    ;)

  • Violet_Z6
    Original Author
    17 years ago

    For those who are fall planting, you may want to check the chart above.

  • belindach
    17 years ago

    A&M is a TX university and has it's own ag department. There is some good stuff here but probably would work best for the south. Sorry, I'm having problems making this clickable.

    www.aggie-horticulture.tamu.edu/extension/vegetable/cropguides/index.html

  • Violet_Z6
    Original Author
    17 years ago

    b,

    It won't work with the "www".

    http://aggie-horticulture.tamu.edu/extension/vegetable/cropguides/index.html

    Here is a link that might be useful: Texas Vegetable Crop Guides

  • Violet_Z6
    Original Author
    17 years ago

    Keep in mind that while they may germinate quickly at these temps, they may not necessarily prefer to continue their growth cycle at the same temps.

  • albert_135   39.17°N 119.76°W 4695ft.
    17 years ago

    I have long had this gut feeling, but only a gut feeling, that many seed sprout faster at temperatures a few degrees higher than on the package or in a data base. My conjecture, but only a conjecture, is that those temperatures were originally from the USDA or some such who were helping agriculturists to get their corps out as early as possible and may be, but are not necessarily, the best temperatures for hobbyists.

  • Violet_Z6
    Original Author
    17 years ago

    There are dozens of grade school science projects which demonstrate similar results. Obviously the seeds don't judge which humans are trying to sprout them.

    Stop by any local nursery, they're starting seeds all the time as well and it's a good way to warm up on a cold spring day.

    While it's not as easy for a home gardener to provide the resources that a lab or nursery might have, it is good to know what the optimum conditions are so that the home gardener can do their best to try to imitate the the closest possible environment they can. And depending on where you are and the resources available, it is not always practical to exert too much effort in varieties not suited to one's region.

    Plants started out in nature in their preferred habitat without the intervention of humans. It's us humans who have taken them and moved them to various locations around the world, far from their native growing conditions. We as home gardeners need to have patience and faith that nature has gone thru a lot of trouble to create a seed that is genetically predispositioned to grow into anything at all.

    The best gardeners I've been around are those who enjoy experimenting. If something doesn't work one year, they'll try another method a different year. Not everything will be a success, and it's the journey that should be cherished.

  • Violet_Z6
    Original Author
    17 years ago

    More info:

    Here is a link that might be useful: The effect of soil temperature on sown seeds

  • Violet_Z6
    Original Author
    16 years ago

    Well, now you don't have to worry about keeping your soil warm so everyone should take advantage and plan their fall crops!